The present invention relates to supplying priming and restitution liquids to extracorporeal blood treatment systems.
The blood and other liquid passages, e.g., the blood and dialysate circuits, in extracorporeal blood treatment systems are primed by being filled with an isotonic fluid, which is typically a sterile saline solution. Priming rinses the blood and dialysate circuits with saline solution, and purges air and particles from these circuits.
Priming liquids are used to prepare extracorporeal blood treatment to receive and treat blood from patients. The priming liquid flows from the bag through the blood and effluent lines, e.g., flexible plastic tubes, of the blood circuit in the blood treatment system. The priming liquid purges air and particles from the lines. Air in the lines could hinder the pumping operation of the system and to avoid infusing air bubbles into the vascular system of the patient. Particles in the lines could clog the blood access device during infusion.
FIG. 1 shows a conventional blood treatment system coupled to a priming bag 12 filled with a saline solution. The priming bag is connected to a pumping and controller console 14 for the system 10. The priming bag is typically a flexible bag sealed to prevent the entry of air and environmental contaminants to the sterile saline solution in the bag. FIG. 1 illustrates a conventional approach to priming the blood treatment system.
The blood circuit is typically primed before blood is withdrawn from the patient 36 into the blood treatment system 10. To prime the blood circuit, a nurse or other medical professional connects the priming bag 12 to the access line 16, e.g., a blood withdrawal tube, for the blood circuit. After priming, the access line is disconnected from the priming bag and connected to the patient 36.
The priming bag 12 is connected to an inlet of a Y-connector 17 that is also connected to the access line 16 and effluent line 42 of the blood treatment system 10. A peristaltic blood pump 18 (such as a roller pump) moves priming liquid from the bag 12, through Y-connector 17, the access line 16 and to a blood inlet port 20 at a lower end of a blood chamber 24 in a blood treatment device 22. The priming liquid flows up through a blood chamber 24, out a blood outlet port 26, and through a blood line 28, a de-aeration chamber 30, a return line 32 and to a collection bag 34.
The flow through the access line 16, blood chamber 24, blood line 28, de-aerator 30 and return line 32 corresponds to the blood circuit, e.g., blood flow passage, through the extracorporeal blood treatment device. In other blood treatment systems, the blood circuit may include other components and have other configurations. For example, the blood may flow downward direction in other types of blood treatment devices. A common characteristic of the blood circuit is that it represents a flow path of blood withdrawn from the patient, through the blood treatment device and returned to the patient.
The dialysate circuit is also conventionally primed with priming liquid from the priming bag 12, which may be the same as or a separate priming bag as used to prime the blood circuit. The priming liquid is pumped from the bag 12 by an effluent peristaltic pump 40 (rotating in a direction opposite to the rotation during blood treatment) through the effluent line 42 and into an effluent port 44 of an dialysate/effluent chamber 46 in the blood treatment device 22. The priming liquid flows through a dialysate/effluent chamber and out a dialysate port 48 of the blood treatment device 22. The priming liquid flows from the dialystate port, through a blood line 50 coupled to a three-way valve 52 directing the priming liquid to the de-aeration chamber 30, the return line 32 and the collection bag 34. A portion of the priming fluid may pass through a semipermeable membrane between the effluent chamber 46 and the blood chamber 24, and into the blood circuit while priming the dialysate circuit.
Similar conventional liquid priming processes may be performed using the liquids in the replacement liquid bag 54 which is pumped by a replacement peristaltic pump 56; the dialysate bag 58 which is pumped via line 59 by the dialysate peristaltic pump 60, and the pre-blood liquid bag 62 which is pumped by the pre-blood pump (PBP) 64. The upper three-way valve 52 and lower three-way valve 68 are switched during the priming operations to ensure that liquids fill all infusion lines associated with the infusion pumps and to avoid pumping air bubbles into the return line 32 when connected to the patient 36. The infusion lines do not include the access line, associated blood lines and blood treatment device.
After the blood treatment system 10 has been primed, the access line 16 is disconnected from the priming bag 12 and connected to withdraw blood from the patient 36, the return line 32 is disconnected from the collection bag 34 and connected to infuse blood and other liquids into the patient, and the effluent line 42 is disconnected from the priming bag 12 and connected to the collection bag 34.
The priming liquid bag 12 is typically discarded after the blood treatment system is primed. The priming bag is typically used only to prime the blood treatment system. Given the limited use of the priming bag, it represents an additional complexity to blood treatment systems, requires that additional supplies be stored for the system and could result in a delay of treatment if a priming liquid bag is not readily available.
Priming liquid may remain in the blood circuit when the blood treatment system is switched to a blood treatment mode. While the priming liquid is typically a saline solution that may be safely infused into a patient, there is a risk that in certain cases the infusion of the saline solution could upset the electrolyte balance in the patient. One such case is when the patient is a small child. Examples of conventional priming systems and method for extracorporeal blood treatment systems include U.S. Patent Application Publication 2008/0237, 128 entitled “Process and Apparatus for Filling and/or Rinsing An Extracorporeal Blood Circuit”; U.S. Patent Application Publication 2009/0101576 entitled “Priming and Air Removal Systems and Methods for Dialysis”, and EP 1 457 218 A1 entitled “Automatic Apparatus for Blood Dialysis and Priming Method Using the Apparatus.”
Priming techniques have been proposed that use the dialysate liquid to prime an extracorporeal circuit in U.S. Pat. No. 5,259,961 (see also EP 0 560 368 A2) entitled “Method and Assembly for the On-Line Flushing and Filling of an Extracorporeal Blood Circulation System of Dialysis Machines”; U.S. Pat. No. 5,490,925 entitled “Assembly for the On-Line Flushing and Filling of an Extracorporeal Blood Circulation System of Dialysis Machines”; U.S. Pat. No. 6,132,616 entitled Method for Flushing and Filling of an Extracorporeal Blood Circulation System of a Dialysis Machine”, and U.S. Pat. No. 6,582,604 entitled “Method of Cleaning and Priming Dialysis System.” These techniques generally apply pressure in the blood treatment device to move dialysate liquid across the semipermeable membrane to fill and prime the blood circuit.